Summary TRD2 will focus on the development of cell lines and advanced optical systems for real-time spatiotemporal control of engineered tissues. Cell lines will be genetically engineered to express bioluminescent proteins for quantitative and real-time sensing, and optogenetic proteins for optical actuation. The hypothesis is that the integration of transgenic tissues expressing these proteins with advanced optical systems will enable real-time feedback control of engineered tissues in a spatiotemporal manner. In conjunction with traditional bioreactors, these systems will allow for the automation and optimization of tissue culture systems capable of rapidly screening many parameters in a variety of contexts. Three specific aims will be pursued. Aim 1: Imaging-enabled bioreactors for disease modeling. A tissue-engineered model of metastatic breast cancer in bone will be used to optimize the chemotherapeutic dose using a feed back control loop for the maximization of efficacy and minimization of toxicity. Aim 2: Optogenetic bioreactors for electrically excitable tissues with feedback control. Using this strategy we will enable directed stimulation and maturation of engineered cardiac and neuromuscular tissues and study the control of cardiac arrhythmias. Aim 3: Bioreactors and implantable devices for excitation/sensing in thick tissues. These capabilities will be used to develop light conduits for excitation/sensing in living tissues and implantable devices for optical actuation. Overall, TRD2 will result in a suite of optical systems, optically active cell lines, and advanced bioreactors for enhanced sensing, actuation, and control in tissue engineered systems. Our initial focus will be on bioluminescence and optogenetics, with the ultimate goal to develop optically compatible cells, biomaterials and devices to interface with engineered tissues, in vitro and in vivo.